I have a panicking program which intends to illustrate the issue of retrieving high-latency resources via golang's http client.
Does someone have a clue why this is happening?
go version go1.5.1 linux/amd64
package main
import ("fmt"
"net/http"
"time"
"net")
func main() {
for i:=0; i<2000; i++ {
start := time.Now()
client := &http.Client{} // this enough for the program to crash
/*client := &http.Client{
Transport: &http.Transport{
Dial: (&net.Dialer{
Timeout: 1 * time.Second,
KeepAlive: 0,
}).Dial,
DisableKeepAlives: true,
DisableCompression: true,
MaxIdleConnsPerHost: 1,
ResponseHeaderTimeout: 1*time.Second,
},
}*/
req, _ := http.NewRequest("GET", "http://mickle.com.au/wp-content/uploads/2015/03/11222.jpg", nil)
req.Header.Add("Connection", "close")
req.Header.Add("Accept-Encoding", "none")
response, _ := client.Do(req)
fmt.Printf("httpreq took %s. resp status: %s
", time.Since(start), response.Status)
response.Body.Close()
}
}
http://play.golang.org/p/nMnFb_x2yU
httpreq took 817.750359ms. resp status: 200 OK
httpreq took 798.177493ms. resp status: 200 OK
[[... left out 33 lines...]]
httpreq took 795.433486ms. resp status: 200 OK
httpreq took 805.610082ms. resp status: 200 OK
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x0 pc=0x4014a6]
goroutine 1 [running]:
main.main()
/home/bongo/Downloads/a.go:32 +0x4a6
goroutine 17 [syscall, locked to thread]:
runtime.goexit()
/usr/lib/golang/src/runtime/asm_amd64.s:1696 +0x1
goroutine 8 [select]:
net/http.(*persistConn).readLoop(0xc8200ac000)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 9 [select]:
net/http.(*persistConn).writeLoop(0xc8200ac000)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 40 [select]:
net/http.(*persistConn).readLoop(0xc8200ac2c0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 76 [select]:
net/http.(*persistConn).readLoop(0xc8200e22c0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 34 [select]:
net/http.(*persistConn).readLoop(0xc8200e2000)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 35 [select]:
net/http.(*persistConn).writeLoop(0xc8200e2000)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 12 [select]:
net/http.(*persistConn).readLoop(0xc8200ac0b0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 13 [select]:
net/http.(*persistConn).writeLoop(0xc8200ac0b0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 16 [select]:
net/http.(*persistConn).readLoop(0xc8200ac160)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 50 [select]:
net/http.(*persistConn).writeLoop(0xc8200ac160)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 38 [select]:
net/http.(*persistConn).readLoop(0xc82010e000)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 39 [select]:
net/http.(*persistConn).writeLoop(0xc82010e000)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 53 [select]:
net/http.(*persistConn).readLoop(0xc8200ac210)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 54 [select]:
net/http.(*persistConn).writeLoop(0xc8200ac210)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 61 [select]:
net/http.(*persistConn).readLoop(0xc8200e2160)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 41 [select]:
net/http.(*persistConn).writeLoop(0xc8200ac2c0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 44 [select]:
net/http.(*persistConn).readLoop(0xc82010e0b0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 45 [select]:
net/http.(*persistConn).writeLoop(0xc82010e0b0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 59 [select]:
net/http.(*persistConn).readLoop(0xc8200ac370)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 60 [select]:
net/http.(*persistConn).writeLoop(0xc8200ac370)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 22 [select]:
net/http.(*persistConn).readLoop(0xc8200e20b0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 23 [select]:
net/http.(*persistConn).writeLoop(0xc8200e20b0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 78 [select]:
net/http.(*persistConn).readLoop(0xc8200e2370)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 62 [select]:
net/http.(*persistConn).writeLoop(0xc8200e2160)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 48 [select]:
net/http.(*persistConn).readLoop(0xc82010e160)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 49 [select]:
net/http.(*persistConn).writeLoop(0xc82010e160)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 28 [select]:
net/http.(*persistConn).readLoop(0xc8200e2210)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 29 [select]:
net/http.(*persistConn).writeLoop(0xc8200e2210)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 70 [select]:
net/http.(*persistConn).readLoop(0xc8200ac420)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 68 [select]:
net/http.(*persistConn).readLoop(0xc820170000)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 69 [select]:
net/http.(*persistConn).writeLoop(0xc820170000)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 101 [select]:
net/http.(*persistConn).readLoop(0xc8201702c0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 71 [select]:
net/http.(*persistConn).writeLoop(0xc8200ac420)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 74 [select]:
net/http.(*persistConn).readLoop(0xc8201700b0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 75 [select]:
net/http.(*persistConn).writeLoop(0xc8201700b0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 84 [select]:
net/http.(*persistConn).readLoop(0xc82010e210)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 85 [select]:
net/http.(*persistConn).writeLoop(0xc82010e210)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 99 [select]:
net/http.(*persistConn).readLoop(0xc8200ac4d0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 100 [select]:
net/http.(*persistConn).writeLoop(0xc8200ac4d0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 88 [select]:
net/http.(*persistConn).readLoop(0xc82010e2c0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 89 [select]:
net/http.(*persistConn).writeLoop(0xc82010e2c0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 80 [select]:
net/http.(*persistConn).readLoop(0xc82010e370)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 77 [select]:
net/http.(*persistConn).writeLoop(0xc8200e22c0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 122 [select]:
net/http.(*persistConn).readLoop(0xc820170160)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 79 [select]:
net/http.(*persistConn).writeLoop(0xc8200e2370)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 116 [select]:
net/http.(*persistConn).readLoop(0xc8200e2420)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 117 [select]:
net/http.(*persistConn).writeLoop(0xc8200e2420)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 120 [select]:
net/http.(*persistConn).readLoop(0xc8200e24d0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 121 [select]:
net/http.(*persistConn).writeLoop(0xc8200e24d0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 81 [select]:
net/http.(*persistConn).writeLoop(0xc82010e370)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 147 [select]:
net/http.(*persistConn).readLoop(0xc8200e2580)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 123 [select]:
net/http.(*persistConn).writeLoop(0xc820170160)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 134 [select]:
net/http.(*persistConn).readLoop(0xc820170210)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 135 [select]:
net/http.(*persistConn).writeLoop(0xc820170210)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 178 [select]:
net/http.(*persistConn).readLoop(0xc82010e580)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 102 [select]:
net/http.(*persistConn).writeLoop(0xc8201702c0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 105 [select]:
net/http.(*persistConn).readLoop(0xc8200ac580)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 106 [select]:
net/http.(*persistConn).writeLoop(0xc8200ac580)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 109 [select]:
net/http.(*persistConn).readLoop(0xc8200ac630)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 110 [select]:
net/http.(*persistConn).writeLoop(0xc8200ac630)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 113 [select]:
net/http.(*persistConn).readLoop(0xc8200ac6e0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 146 [select]:
net/http.(*persistConn).writeLoop(0xc8200ac6e0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 140 [select]:
net/http.(*persistConn).readLoop(0xc820170370)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 141 [select]:
net/http.(*persistConn).writeLoop(0xc820170370)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 144 [select]:
net/http.(*persistConn).readLoop(0xc820170420)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 145 [select]:
net/http.(*persistConn).writeLoop(0xc820170420)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 94 [select]:
net/http.(*persistConn).readLoop(0xc82010e420)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 95 [select]:
net/http.(*persistConn).writeLoop(0xc82010e420)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 162 [select]:
net/http.(*persistConn).readLoop(0xc82010e4d0)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 163 [select]:
net/http.(*persistConn).writeLoop(0xc82010e4d0)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 179 [select]:
net/http.(*persistConn).writeLoop(0xc82010e580)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 126 [select]:
net/http.(*persistConn).readLoop(0xc82010e630)
/usr/lib/golang/src/net/http/transport.go:976 +0xac7
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:685 +0xc78
goroutine 148 [select]:
net/http.(*persistConn).writeLoop(0xc8200e2580)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
goroutine 127 [select]:
net/http.(*persistConn).writeLoop(0xc82010e630)
/usr/lib/golang/src/net/http/transport.go:1009 +0x40c
created by net/http.(*Transport).dialConn
/usr/lib/golang/src/net/http/transport.go:686 +0xc9d
exit status 2